Histologic Retinacular Changes Associated With Ischemia in Painful Patellofemoral Malalignment

Abstract

Ischemie changes in 31 samples of lateral retmacula excised at surgical realignment in patients with isolated symptomatic patellofemoral malalignment resistant to conservative treatment were evaluated with conventional histology, electron microscopy, immunohistochemistry, and molecular biology. Morphologic and ultrastructural changes associated with ischemia including hypervascularization and increased vascular endothelial growth factor release were identified in painful patellofemoral malalignment. It is hypothesized that periodic short episodes of ischemia could be implicated in the pathogenesis of anterior knee pain in most cases of isolated symptomatic patellofemoral malalignment in active young patients by triggering neural proliferation.

Blood perfusion of patellar bone measured by dynamic contrast‐enhanced MRI in patients with patellofemoral pain: A case–control study

“…It has been hypothesized by Sanchis-Alfonso et al that episodes of ischemia, possibly due to vascular torsion during sitting, could trigger hypervascularization of the patellar retinaculum in maltracking patients with PFP as a result of increased vascular endothelial growth factor release. 33 This might also be applicable for the patellar bone. Another explanation for hyperperfusion could be the presence of bone marrow lesions (BMLs).…”

Patellofemoral pain: Is malalignment sufficient to uncover the reason for pain? Terminology, pathophysiology and nociceptive mechanisms

“…Daha sonra yapılan çalışmalarda da lateral retinakulumda dejeneratif nöropati geliştiği, amputasyonlar sonrası gelişen nöropatiye benzer değişiklikler oluştuğu gösterilmiştir. [7,11,12] Bu sinir hasarı sonrasında derin duyunun (propriosepsiyonun) bozulması beklenebilir. [10] Nitekim patellofemoral ağrı sendromu olan bireylerde eklem pozisyonu hissinde anormallik gösterilmiştir.…”

“…Ciddi diz önü ağrısı olan hastalarda lateral retinakulumdaki sinir sayısı artmaktadır. [12] Bir başka çalışmada substans-P liflerinin (ağrı duyusunu uyaran nörotransmitter) diz önü ağrısı olan hastalarda lateral retinakulumda medial retinakulumdan daha fazla olduğu bildirilmiştir. [14] Bu çalışmada sinirlerin damarların çevresini sardığı ve yeni sinir liflerinin olduğu gözlenmiştir.…”

Medial and Lateral Patellofemoral Joint Retinaculum Thickness in People With Patellofemoral Pain: A Case‐Control Study

“…3,4 Structural changes within the lateral retinacula have been proposed as possible sources of symptoms and potential targets for treatment. [5][6][7][8] Patellofemoral pain is characterized by an insidious onset of anterior or retro patella knee pain, without intra-articular or peripatellar disorders. 9,10 Commonly described as an overuse condition, increases in pain are often associated with activities including walking, running, squatting, and stair climbing.…”

“…15,16 During repetitive functional activities that load the patellofemoral joint, altered mechanics can result in elevated joint stress [16][17][18] and chronic lateralization of the patella, which results in adaptive shortening of the lateral retinacula and stretching of the medial retinacula. 19 As a consequence, these altered mechanics have the capacity to drive a loss of tissue homeostasis of the underlying subchondral bone and initiate neural changes within the retinaculum tissue, 5,20,21 representing pathways to nociception and subsequent patient-reported symptoms.…”